In relation to the specific review I normally acknowledge the comment, advise the employee that their concerns will be investigated and ask them to get in touch with HR to provide more detail. I then refer the complaint to the appropriate manager and ask them to investigate even if we get no further information.

I also look for overall trends in reviews - are employees making comments about the same managers, policies or processes? Is there anything I / the Company can do to try and resolve commonly raised issues?

there are a number of threads on this, this one may be a good place to start

Indeed is a little different to Glassdoor in that - assuming you have an account with them and aren't just a free user - they will actually allow you to re-set your company page to remove negative comments (and positive ones, though).

However, before leaping to this, you - and your business's leaders - need to appreciate some important points:

1. No one is 100% popular with everyone. This is especially true with employers. High ratings are suspicious and an absence of negative comments will make your profile look insincere.

2. You can respond to negative criticism. Doing so honestly and constructively says more good things about a company than eliminating it does.

3. You can encourage people to leave positive feedback so that the negative feedback looks like the minority voice it ought to.

4. You can't control your public profile by pretending it doesn't exist. Imagine advising a restaurant that had bad feedback on TripAdvisor. Should they hire a PI to discredit their critics? Or bribe a TripAdvisor employee to delete bad feedback? Or should they just try cooking better food, improving their hygiene rating and training their waiting staff to be more polite? Likewise with employers. If you want a better rating, try being a better employer!!

In reply to Robey:

Completely agree Robey!